Model railroading is a widely practiced hobby, allowing the hobbyist individually to build or purchase miniature models of railway cars, engines, track layouts and settings, for use either for display only but more commonly and primarily for use as an operational system. Different standard scales have evolved, but each is substantially smaller than the full scale size of working railroad equipment, to the extent that the cars commonly would be a few inches long to a foot or so long. Nonetheless, the accuracy of model scale-down and realism to the real equipment is followed as much as possible. Thus, the model car components, including the operational truck assembly comprised of the wheels, axles and bearing mounts therefor, become very small, as accordingly does the track gauge.
For the system to be operational, such as where the cars can freely and reliably roll along the tracks, proper tolerances of the truck assembly components is critical. This includes tolerances not only of new truck assemblies, but also assemblies used by running them around the track layout awhile. Also, lubricant commonly can be applied to the truck assemblies to reduce wheel rotation drag. Due in part to the small component sizes, excessive lubricant application and leakage are common.
Lubricant leakage can coat surfaces of both the wheels and the tracks. Also, wheel rotation over the tracks may generate a static charge on these components. Either or both of these factors seems to draw dirt, dust particles or the like to the wheel assemblies during and after train usage, which over time accumulate as solid tar-like or gummy particulate buildups on the wheels and tracks, and at the wheel bearing mounts.
With the model sizes involved, even minor particulate buildups create major operational problems, such as increasing wheel drag and/or even causing car derailments.
Further, particulate buildups can be and are typically unsightly, modifying what could or should be shinny track or metal wheel surfaces, for example to a dark tar-like color.
Removal of particulate buildups from the tracks is possible and relatively easy, as the track surfaces are exposed, accessible and generally stationary, and with equipment no more complicated than a suitable solvent and an applicator/scrubber. Moreover, equipment suited to clean tracks is now commercially available.
However, cleaning the wheels and bearing mounts of the truck assemblies is a different matter. For example, the wheels have very small tread and flange surfaces, and only part of these surfaces are exposed at any time and the rest are inaccessible within the truck assembly. The bearing mounts are always inaccessible. Further, the truck assemblies and in fact the car itself, again because of the sizes involved, are not suited for rough handling in holding the car and manually abrading and/or removing the particulate buildups. Besides, each train car will typically have two truck assemblies, each with four wheels, meaning that many inches of wheel surfaces would need cleaning for just a small collection of cars, despite the scale.